


The Eggscellent Adventures of Undyne and Alphys

by feralphoenix



Category: Undertale (Video Game)
Genre: Alphynecentric, Alternate Universe - Everyone Lives/Nobody Dies, Awkward Sex, Come Eating, Egg Laying, Eggpreg, Explicit Sexual Content, F/F, Impregnation, Post-Canon, Spoilers - Undertale Pacifist Route, Xeno
Language: English
Status: Completed
Published: 2018-02-17
Updated: 2018-06-27
Packaged: 2019-03-20 06:48:19
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 5
Words: 13,536
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/13712184
Author URL: https://archiveofourown.org/users/feralphoenix/pseuds/feralphoenix
Summary: A few unrelated shorts on the general theme of Undyne and Alphys having some eggsciting new life adventures postcanon.





	1. sunny side up

**Author's Note:**

> _(laugh at life’s realities_ – just enough wind to keep the whole sea in motion, to make the waves come bounding to the shore, foaming and sparkling, as if wild with glee.)
> 
>  
> 
> **A FEW GENERAL NOTES OF INTEREST BEFORE WE GET INTO THE ALPHYNE EGGSTRAVAGANZA:**
> 
> 01\. both alphys and undyne's anatomy are veeeeeeeeeeeery loosely based on that of real-life monitor lizards and fighting fish, with some (a lot of) fudging to account for their humanoid bodies.
> 
> 02\. for those who are not familiar with how i handle monster gender, here's the cliff's notes version: monsters do not assign gender to babies based on genital appearance, they choose their own genders as children; therefore there is zero correlation between a monster's gender and what sort of junk they've got and no one is cis. for the purposes of these ficlets, whether undyne and alphys are individually egg-producing or sperm-producing will vary because i'm not married to my headcanons for them the way that i am with the boss monsters. however, due to the nature of these stories at least one of them will be egg-producing in every story.
> 
> 03\. there will not be any oviposition here--sorry! for safety's sake i'm erring on the side of toys in a cloaca being treated the same way that toys in a butt should be treated, i.e. if it doesn't have a wide base, don't put it in. that means egg insertion is a no-go.
> 
> 04\. **ADDENDUM:** the "minor or background relationships" indicated in the relationship tags are frisk/chara/asriel and toriel/sans/asgore, just in case either is anybody's not3. both get a couple of offhand mentions when characters are talking about the relationships that they're in.
> 
> with those caveats in mind, though, have fun...!!!

Alphy built the tank.

It was the weirdest and most ticklish thing you’ve experienced maybe ever, looking stuff up on the transplanted undernet servers for reference materials and checking the list of extended family you’d be willing to contact for advice. You got junk food all over her blueprints while you shared notes and she checked and rechecked her measurements, cool hands braced on your legs while she fiddled about with the tape measure.

All in all the tank had to be narrow enough for you to straddle comfortably, high enough that you could balance without having to squat, but also low enough for Alphys to be able to reach it without having to sit on a chair. Long, too—at least from everything you’re aware, only kids like you’re outliers, and you should expect more like three to five, so there needs to be enough room for ‘em.

There was nothing about salinity anywhere, so in true scientist style Alphys prepared glasses of water with different amounts of salt in ‘em and had you stick a finger in, confident that you’d be able to tell instinctively what the right range would be. She put together plans for water filtering so that you wouldn’t have to worry about moving things around, which is something you’d never even considered. She’s so smart!!!!!!!!!! BETWEEN HER SHEER BRAINS AND YOUR BRAWN, YOU’RE GONNA HAVE THE MOST POWERFUL KIDS EVER!!!!!!!!!!!!!

Kids have been an unchecked mark on your marital to-do list for, god, ages now??? Since before you started talking seriously about marriage, even. Alphys probably vaguely knew you wanted some ‘cause she knows you like kids in general, and she did say to you that she wouldn’t mind considering it if she ever got her life on track, and you talked about it casually and then more seriously as your relationship itself got more serious and you got engaged. Then when you got married the topic got shelved for a while. You were both busy with work, and then strengthening your house so that you _wouldn’t_ keep destroying it with enthusiastic cooking and/or science, and kids needed a _(God,_ though it makes you sound like Papyrus’ ridiculous brother) nest egg that you just didn’t have ready.

But now you do have the money, and the time, and the stability. IF THIS ISN’T GO TIME WHAT IS????????

There’s just… _one_ tiny little snag in the process of having as many of Alphy’s babies as you could ever possibly want.

This is that procreation is a little difficult to rub one out to.

And you _do_ gotta rub one out, which is the problem: Maybe this woulda been easier if you and Alphys could just have sex the way you usually do, but you specifically need to come in the tank instead of in your wife’s mouth or against her leg or a pillow. You _can,_ theoretically, get off without that sorta consistent pressure over the entirety of your crotch, but it’s difficult to if you’re not super horny already.

And concentrating on your desire to have babies, which you have GOT to do if you want your roe to be viable, kills your boner _just_ enough that you can’t get off.

The last time you tried you just squatted over the tank fingering yourself with Alphy sitting at her desk keeping an eye on you for fifteen whole goddamn minutes until her struggle to keep a straight face finally cracked you up, and then you spent another five minutes both cackling ‘til you started tearing up, and welp. You’d officially missed the train to nut city.

Complaining about the state of things is unnecessarily difficult, too. Like, you don’t wanna unload to Alphys and make her feel like this is her fault or something—she’s miles better at not immediately blaming herself for everything than she was when you first met, but she’s still a sensitive person, and she still slips.

Papyrus is the person you generally whine to, but you think he’s still not even completely convinced that sex is a real thing and not something Sans made up to prank him. It makes the topic a little hard to bring up.

Chara… well, they’re grown up now so _theoretically_ you could have conversations about sex with them, and they specifically come hang out with you and Alphys when their partners are doing kinky shit that they need to avoid and all. But also human fertility is totally different from how things are for monsters, and you’re the one who took them down to the pharmacy in Ebott City to pick up what they called the “morning after pill” the one time they had a scare, and… even thinking about their expression back then makes you feel like it’d be insensitive to complain.

Which leaves Asgore, to whom you could also _theoretically_ talk about sex, but like???? The one time you tried you only got as far as saying that having babies was more awkward than you expected before embarrassment shut you up.

“I believe that I, er, ‘know that feel’,” Asgore had replied at maximum bashful, avoiding your gaze. “It was a very long time ago, but Tori..el and I had similar trouble when we, er… When we were planning for Asriel.”

“Huh,” you managed to get out, a bit curious as to what he meant because from what little you know about mammalian monster sex it seems like that would be less of a problem but still not curious enough to ask.

“I am sure that the two of you will be able to work things out eventually,” Asgore went on, avoiding your gaze even harder. “I, er, wish you luck.”

“Uhhhh, thanks???” you said, and then you continued the walk you’d been on for five minutes in horribly awkward silence before you came up with a new topic of conversation and never mentioned sex again with mutual earnestness.

_Anyway,_ the issue remains that thinking about babies is the opposite of sexy. It’s great for inducing warm fuzzy feelings so mushy they’re downright embarrassing, and it’s great for making you nervous and excited?????? But literally NONE OF THAT helps you get off.

“M-maybe this means I should help after all,” Alphys says when you give her the abbreviated version of this, minus any mention of your wimpy ill-considered attempt at commiserating with your old mentor who’s _basically your honorary dad, shoulda thought that one through first, Undyne._ “N-not!! Not in a sense of ummm, of eating you out o-or anything b-because we _know_ why that’s uhhhhh, n-not c-conducive t-to getting anything into the t-t-tank. But. More f-foreplayish b-body worship? Maybe?????”

“I’m willing to try just about anything at this point, Al,” you say, shaking your head. Earlier you let her put your hair up in some sorta elaborate braided knot at the nape of your neck to keep it from trailing into the incubation tank, and it’s weird to have the unmoving weight there where normally your ponytail would be swaying back and forth. “’Cause we keep trying and it keeps not working and I’m starting to feel real dumb.”

She reaches out and pats at your face in some completely adorable attempt to shush you. “I-I know. I-I feel d-dumb too! So at least it’s nice to, uh… t-to know that I’m in g-good company? Eheheh…”

You reach up and trap her soft squishy arm before she can retract it, and give her palm a firm smooch. She squeaks, and you grin. “Like, god damn,” you say. “I think you may be onto something there—of course I’m excited to have your beautiful babies but, like???????? I shouldn’t be so excited that I wanna fast-forward through sex with YOU to get to ‘em. Maybe this just needs to… I dunno, feel more like sex with you than me trying to jack off by myself when I’m not really feelin’ it, y’know?”

Alphys gets steadily redder and redder as you speak, but by the end she’s starting to grin too. “Awwww,” she says. “T-that’s really sweet, Undyne…”

Even after literal actual years of marriage it’s still knee-jerk to try to shut her up when she starts cooing over the soft side you try very hard not to display in public, but after all this time it’s at least easier to quash that urge without showing it on your face. “Yeah?” you say instead, voice low, grinning more broadly.

“You really—” she pauses to kiss your cheek— “really—” she pauses again to nuzzle the corner of your jaw— “are.” And she kisses the side of your neck here, trailing tiny little pecks down to the muscles of your shoulder.

Just her voice, just her hands and her mouth on you, are already making a huge amount of difference: Where you weren’t feeling anything before, now your crotch is tingly-sensitive and running your fingers in idle spirals over and around yourself aches. Your belly feels _full_ in a way you’re only really ever aware of when you’re horny, the knowledge that your body’s heavy with roe that wants to come out, that you wanna _let_ it out, all at once in one big gush.

Alphy’s still kissing and nibbling at your shoulder, but she sets her hands on your sides, claws light against the edges of your gills. She’s careful, knows they’re sensitive, so the soft tapping of her fingertips is just enough to spread the faint tingles all through you, to tease.

Your mind’s on the edge of straying into the land of 120% horny, and if you go there you’re probably not gonna get out, and you’ll just feel EVEN DUMBER that having Alphys help you didn’t work. So you wrap your free arm around her squishy waist and hold her: Little and cool and soft.

She’s so brilliant, and so—so witty and passionate and vulnerable. She’s always made you feel tender, made you wanna give her the best of yourself, by helping her physically or emotionally or by being a better you. By making her feel good, and by _literally_ giving her the best of you when you come.

Fuck. _Fuck._ Your hips chase your hand automatically when you think that, and your belly coils urgently, the tips of your fingers getting slick. Hot damn, you’re no Alphys but just maybe you’re on the edge of cracking the code, here.

You wanna give her the best of you, so she’ll give you the best of herself, too, so your come can mix together in the water and the best of both of you’ll take the shape of your future. Alphy’s hands slide down to your hips, and she presses her forehead to your bare chest, nuzzling, making a happy sound deep in her throat; you grip the back of her coat and grunt. Almost there. She’s pressed against you so close and you’re so full of love and you _wanna_ come but it’s so slow to push yourself all the rest of the way with just your fingers—

“Undyne,” Alphys murmurs, her breath a soft caress of air down your stomach. You shiver all over.

She shifts her hands to grip both cheeks of your ass, and your breath catches in your labyrinth, and she nuzzles your belly again and starts to caress down the backs of your thighs and—you grunt and buck into your hand and shuddering all over, you come.

Even in spite of everything, you still jump a little at the thick wet plops your roe make as gobs of the stuff drop into the tank between your shaky legs. You shift your grip on Alphy’s coat and arch your back, breaths coming out in stuttery huffs as you disgorge clouds of the tiny pearly eggs, none bigger than the claw on your little finger, a dizzying release of pressure in your abdomen. Your muscles spasm over and over.

Finally, once you have nothing left to come, you let yourself sag against Alphys’ shoulders. Your whole body’s filled with a floaty detached sensation, spreading through you in throbbing ripples like the water’s surface after somebody chucked a rock in.

“Y-you did really great,” Alphys is saying. She shifts her arms to hug you around the waist and lets you stay draped over her like a second shirt.

“Thank fuck,” you slur when you feel steady enough again to be confident in the use of your voice. “Now we can finally go back to doing it like normal people once you take your turn.”

“Oh,” Alphys says. You straighten up and stagger back so that you’re not going to be looming over the tank anymore, so she’ll have a clear shot. Not like it’ll be easy to _miss,_ ‘cause even despite the size of the tank itself you managed to pretty much coat the whole surface of the water. “Hm.”

You think you know that baffled tone. “Al?”

“I-I just s-suddenly have!!! An ap-preciation for how awkward this, uh. Actually is.” She gestures aimlessly and lets her hands fall to her sides, spread palms clapping against the scales of her thighs. “It’s, uhhh. It’s n-not c-coming out.”

You follow the line of her stare down the open front of her lab coat, across the pale scales of her belly down to the seam of her cloaca. The lips are parted, letting a sliver of pink skin peek out, and the two round heads of her forked dick are peeping from underneath, making the rolls of skin bulge suggestively, but liftoff is super not happening.

Part of you’s a little tempted to be like _see, I told you!!_ but you don’t wanna make her feel bad or anything, so. “They say one good turn deserves another,” you tell her winningly. “I could help.”

Alphys turns and gives you this half-lidded Look, and if you could package smarm her face right now could probably save the whole world from any potential smarm shortages in the next couple centuries.

“Yeah,” she says, smiling. “You c-could help. This is g-g-gonna have t-to be a group effort down the line anyway, s-so might as well start now, right?”

“Having babies is so fucking magical and romantic,” you say. Alphys shrugs out of her lab coat and hands it to you; you drop it casually over her chair and then stand behind her, straddling her tail, wrapping your arms around her shoulders and middle with the good side of your face pressed against the flat part of her frill. “This is gonna be a great family story one day, I bet.”

She starts to giggle. It vibrates through your chest and stomach, and you kiss the side of her face. “G-god, we are _so_ not turning this into a family s-story. Even with everything it’s t-too X-rated! You c-can’t even _swear_ in front of k-kids, so how are you g-going to tell them that M-mom and Mommy c-couldn’t get it up to make them for _ages???”_

“Eh,” you say winningly. “I was kinda hoping you’d be doing the telling, Alph.”

“Absolutely n-not.” You sweep your hands up and down her bare belly and chest, the softness of her flesh under her scales, keeping the pressure gentle; she sighs. “W-we want to, ahh, a-at least have SOME appearance of c-c-competence in front of our, of our own _children.”_

“That works too,” you agree, and drop your chin so that you can gently rake your teeth along the ridge of her shoulder. Alphys makes a little fluttery _oh!_ that burns between your legs, and though it’s hard to see past the other side of your face, you can see the two heads of her cock have emerged into open air. It’s so _fucking_ cute how it does this, like slowly luring something shy out by encouraging it. You lift your left hand up so that you can lick your fingers thoroughly, still stroking Alphys’ belly and thigh with your other hand. “We’re gonna make some great kids, babe.”

“It’s _so_ weird talking about this when you’re feeling me up,” she mutters. “B-but d-don’t stop or anything, okay? I might, uh, get distracted.”

“I know how it goes.” You don’t touch her cloaca directly but you do rub her belly above and beneath it, waiting for her dick to fully emerge. She shudders against you, the breath hitching noisily in her lungs; you get back to kissing and nibbling her shoulder and the side of her neck. Strands of hair are coming loose from your bun, tickling your bare back, distracting you.

_“Undyne,”_ Alphys breathes. You lift your head to look, smile down at the dainty pink Y of her penis, and reach to gently fit your wet fingers around it. You don’t close your hand or try to squeeze—you learned hella fast in your thankfully long-gone sex noob days that it’s work too fine to rely on your sense of how much strength to use, which can be pretty wonky when you haven’t got direct sensory feedback.

You don’t need to squeeze, though. Just running your fingers idly back and forth over the shaft, the joint where it forks, the edges of the two heads, and the lips of her cloaca is enough to make Alphys squeak and shiver, twitching against your palm. She grips your forearm in one small hand, claws digging in just a little.

“We’re gonna be,” you whisper low against the side of her face, _“so happy.”_

Alphys shuts her jaws with a click and whines just once, high and urgent. She jumps in your hand, and you watch as two thin streams of glossy white come arc in the air and splatter across the water in the tank that still bloats with clouds of your roe.

You drop her dick, and she rests her weight against your chest; you shift your feet to brace yourself and better support her. And you stand like that for a while, spaced out, breathing, staring at the tank.

“Sure hope that worked,” you say at last.

“It, uh,” Alphys says, still breathless, “ought t-to have. I-I mean I have no id-dea how many of the uh, of the eggs will h-have been f, been fertilized, b-but???? Y-you laid a metric f-fuckt-ton of them and I c-came on them and we were b-both thinking about wanting k-kids, so??? W-what else d-does the world _want_ of us.” She pauses. “I-I wonder how many w-will actually be, um. How many we’ll have.”

You shrug. Aquatic monsters like you lay tons of eggs because back in olden times before you had convenient incubation tanks there was a high chance of them getting eaten by animals or ruined by weather, and especially with amphibious crossings like you and Alphys it’s apparently a crapchute as to whether her sperm’ll actually fuse with the eggs before they stop being viable. “It’s pretty rare to have more than six even in dramatic cases. Three to five’s most likely. But we should be able to see what’s going on here in a couple weeks.”

“Much more accurate than having to g-guess at what’s going on inside a mammal womb,” Alphys agrees happily. “And we can… uhh, I guess we can m-make more detailed plans after that.”

You fold your arms companionably around your wife’s waist. “And at least until then, we get to go back to having _normal sex.”_

She snorts and pats at your arm. “Yeah, like, thank _god.”_

But for all that, you keep standing there and gazing down at the tank in peaceful silence for several more minutes. After coming this far? It’s hard _not_ to be optimistic.


	2. hard boiled

“Undyne?” Alphy asks you one day apropos of nothing, looking up from her paperwork at you just as you sit down at the piano bench. “What would your, uhh… opinion be on me showing you s-something that’s maybe a little weird, but, uh, hopefully also hot?”

“You’ve followed me faithfully on plenty of Weird But Hot adventures, so it’s about the least I can do to thank you???” you say, craning your neck so that you can look her properly in the face. “As long as it’s not, like, something you KNOW I can’t do?”

“Oh!! N-no, it’s nothing like that,” Alphys says, dropping her papers and waving both hands earnestly. “It’s more like… what would you, uhh, think ab-bout… there b-being a, uh, a way for you to t-tell exactly how many t-t-times I’ve, uh, g-gotten off over the p-past, uhh, month or so?”

“Definitely hot?????” you tell her.

“Even if it’s… a v-very lizard monster thing?” she presses.

“Probably still hot,” you assert.

She seems to consider this. “Well! W-well. I guess we can!!! T-test your thesis this weekend. Saturday night to be eggs-act.”

You narrow your eye at her across the room. “Alphys, did you just try to foreshadow your big surprise with a shitty egg pun.”

“I’M BLAMING THIS ON SANS BECAUSE HE NEVER STOPS AND NOW HE’S GOT ME DOING IT,” Alphys says very loudly, and buries her nose in her papers again.

You consider your piano for a moment, then grin and turn back to Alphys, cupping your hands around your mouth so she’ll hear you when you stage whisper _“Still hot!”_ in her direction. She colors and sputters but doesn’t look at you, so you guess that’s basically gonna be that.

 

 

Saturday Alphys exiles you from the bedroom to get set up, and since you won’t be able to concentrate on any actual important tasks around the house while you’re busy anticipating, you make like Papyrus and clean instead. This way you get to put your energy into doing something productive, and it keeps you from idly going off to wank and risking either not being available when Alphys wants you or getting called right when you’re satisfied and won’t want sex until you’ve had a chance to get good and horny again. It’s excellent planning on your part and chores are getting done too, so basically everyone wins.

She finally calls for you at a little after three in the afternoon, and you nearly trip on your own feet rushing up the stairs to join her.

Alphy’s lounging on the bed naked, sitting up with her legs spread and the lips of her cloaca puffy and parted like she’s been fingering herself up until you opened the door. Her breathing’s deeper than usual, and her eyes are a little unfocused-looking, the pupils dilated and her glasses slipping down her snout.

You strip off your clothes and dunk them one-handed into the hamper at the wall (you hit the backboard of the little toy basketball hoop above it, and everything swishes satisfyingly through the net to drop with a _flumph_ onto the clothes pile). It’s not until you sit down that you realize from the texture she’s set towels out over the bed, neat as a patchwork quilt or something.

Alphys looks at you, and you pretzel your legs and regard her back, resting your arm on the cool metal frame along the side of the bed. “Sup,” you say, grinning wide. “So what are we doing here? Lay it on me.”

Even in her state she rolls her eyes and groans. “D-don’t give me that when you so obviously already _know,”_ she scoffs.

“Yeah, but like, you wanted to give me a run-through before the show starts, right???” you press, trying for winning, probably failing but hopefully at least not falling into too douchey a range. “I wanna get the instructions and warnings or whatever before we embark on this wild journey. Like am I just supposed to watch or is there something I oughtta be doing to help or?????”

You raise your eyebrows at her expectantly, trying to verbally plaster on as many question marks as you can. Alphy rolls her eyes at you in exasperated fondness and paws at her glasses, shakily straightening them on her face.

_“So,”_ she says. “S-so, obviously you know a l-lot of monsters whose bodies p-produce egg cells ovulate at, uhh, some point d-during sex. Or, or masturbation really, j-just at some point of the arousal cycle in, ahh, in general.”

You nod here, because yeah, that’s been your body since you were about twelve or so.

“We _think_ it’s a v-vestigial b-bodily function from b-before we d-developed such strong magic b-because it happens regardless of whether we’re fertile or n-not, but uhh, I think if you w-w-want the uh, the evolutionary b-biology lecture you’re g-gonna have to ask for it later??” she goes on, squirming, making a face and flapping a hand at the distraction. God, it’s adorable how she can never quite hold back the urge to infodump. “Basically!!! F—for lizard monsters like me w-we uhhh, we ovulate o-on orgasm. S-so whenever we uh… whenever I g-get off, t-that forms an unfertilized egg, a-and after they… d-develop, obviously they have t-to come out.”

“So far I agree with ‘weird but hot’,” you agree. “So they all like… you lay ‘em by month and not just like, X days after they form??”

“In m-most cases,” Alphys explains. “The slugs—the b-blanks, you know, the uhh, the unfertilized eggs, they’re way smaller than a-actually fertilized ones, and I think that’s p-part of it. Obviously f-fertilized eggs would have hormonal effects on my b-body and all that too??? But like????” she paddles her hand in the air again and shakes her head. “Laying unfertilized eggs is, it’s m-much safer t-too, like egg-binding from it’s _virtually_ unheard of b-because they’re so much smaller.”

You narrow your eye a little dubiously at her, because you know what egg-binding is. “But this doesn’t like… _hurt_ you or anything, does it???”

Alphys looks you in the face and blinks, wide-eyed. “Oh! N-no, it d-doesn’t _hurt._ It’s a uh, a good idea to have a muscle relaxant on hand in case of emergency l-like you would if you were actually laying fertilized eggs and all b-but it’s not _painful,_ slugs are t-too small.” She smiles here. “M-most people say it’s, uhh, just a little unc-comfortable, ab-bout the same as processing human food??? And some people, uhh… sort of l-like it, actually…”

Seems like you’re not gonna have to guess which Alphy is. Still, you’re glad—it’d haunt you if every time you had sex you were actually setting her up for pain later.

“Okay then,” you tell her. “Is there anything you need me to do, or should I just watch then?”

“Probably better if, uh, you don’t touch me down here while I’m, y’know, y-you wouldn’t w-want to break them or p-push them back in b-by accident—oh!” Alphys’ body jolts, and she reaches for your hand, grabbing at your fingers. You wrap yours through hers and hold it tight; her eyes have slid back out of focus but her voice is heated and the way her breath goes rough is exactly the same way it does when you’re having sex.

You stare down at Alphy’s crotch in stupefied fascination, your ability to words momentarily dropping out on you. The first egg is _visible_ from inside her, bulging the sides of her cloaca outwards, pale. Her toe claws curl and she clenches her fingers on your hand, and her whole body shivers like she’s pushing, and it sort of sits in the seam of her body for a minute and then softly comes out, dropping with neither pomp nor circumstance onto the towels.

Alphys sighs and relaxes. You squeeze her hand back and ogle the egg.

When she said _egg_ and _smaller than a fertilized one_ your brain automatically went to the chicken eggs the two of you buy to make food from and even sometimes manage to not burn to a crisp. This is smaller, though, almost as little as the candy-coated chocolate eggs Chara’s had you raid from corner stores to send to them after the human holiday called Easter, when they go on sale. You could probably hold three or four of ‘em easily in one fist. The shell’s off-white instead of being light brown, too, and has tiny black speckles.

And it’s all _wet and sticky_ from having just come out of your girlfriend, the kind of wet and sticky your fingers get when you’re feeling her up when she’s horny.

_“Whoa,”_ you say.

Alphys giggles, pitched nervous, but the look on her face is still pleased. “I’m g-glad you’re not weirded out.”

“Well, yeah, it is kinda weird, but I think I can definitely get into this kinda weird,” you tell her. “What’s it _like?”_

She snorts. “What’s it like for _you_ to get all filled up with roe and then s-spawn them? It, uhh, it t-takes longer, but it’s g-got to be the same kind of thing p-pretty much, doesn’t it?”

“I dunno! How about you describe me the experience and we can _compare notes.”_

“You get, uhh. Heavy and full, as they pile up inside,” she says, looking you straight in the eye. “It’s nice to feel so stuffed a-and it’s nice to, ahhh, to get them out b-bit by bit.”

The way she says it, the words she _chooses,_ tingles in your gills and burns between your legs. You’re not in any position where you can surreptitiously wiggle against anything for pressure because you’re a DUMBASS and you never think enough before jumping into anything, but whatever, you’ll survive. Alphy goes all shivery and grabs your hand again, and fascinated, you watch as she pops another egg out, rolling to a stop next to the first.

It’s quiet in the room except for her heated breathing and the creak of the mattress as she fidgets, her soft sounds of effort, the wet click of eggs dropping from her body that sound almost like chicken eggs bumping each other in a carton. There’s probably some acoustics thing to do with the size and how the room is set up and how damp they are that Alphys could science to you later if you asked. But you just sit and let her get on with it. She leans her upper body against the metal bedframe and the wall.

The pile’s getting to be pretty tall now. Most if not all of these things are proof that you made her feel good—you guess you can’t take credit for _all,_ Alphy’s a fairly randy person and has plenty of porn games to jack off to if you’re out or not in the mood. But she said _about a month_ and if that means thirty-ish days—you’ve definitely had sex each day for maybe three quarters of that amount of time, gotten her off at least once each time you had sex.

It’s weirdly hypnotic watching her push the eggs out. She’s got that kinda face on that she does when she’s coding and gets In The Zone, worrying her lower lip with her teeth, focusing on your chest or something instead of your face. She opens, closes, but never all the way, always braced for the next: This is what a cloaca’s _for,_ really, not just for you to put your fingers in and play find the hemiclits, which is something that hadn’t occurred to you til now. You don’t know whether you feel turned on or just tender.

“Do you want to t-try catching one?” Alphys says out of nowhere and about startles you out of your scales. In truly badass fashion, you manage to refrain from leaping sideways off the bed like you’re doing an impression of Endogeny.

_“Catching_ one????” you repeat, raising both eyebrows and staring at her.

“Y—yeah, if that’s not t-too—”

“It’s not too,” you interrupt, wanting to head off that uncertain look in her eyes as soon as possible. “I’m game, what should I do here?”

Alphys reaches out to grab the hand she’s not already holding, and guides you to hold your palm at an angle to and a little below her cloaca. She doesn’t let go of you, just keeps her hand on your wrist, and she squeezes it when she strains.

The egg stops half out, like someone tired from reaching the top of a hill, and then it wiggles a little and drops.

You jump not altogether voluntarily: Now that it’s actually in your hand, your fingers curling instinctively to keep it from rolling and getting stuck underneath her, you realize it was pretty dumb to expect it to be cold instead of body temperature. But it’s warm, and very sticky, and you sorta roll it between your fingers experimentally. Maybe it’s because it’s just been laid but it feels weird and leathery, almost, a texture you’re not sure if you wanna drop or keep playing with.

Alphys sighs and droops until her forehead hits your shoulder. “Think that was the last one,” she says, sounding all dreamy like she does after you’ve been banging. “Gonna have to rest for a while before we do anything ‘cause _man_ do you get, get sore after popping out a whole batch, b-but _oooooh my god_ it’s gonna be good when you fill me back up later.”

“Shit, that’s hot,” you say out loud. The last egg is still in your hand, and you sorta stick it on top of the pile, not wanting to clench your fist thoughtlessly and smush it. You know there’s nothing in there and all, but the thought still feels shocking.

“So what do you think?”

She’s too calm to stammer much, which doesn’t happen often but is hells of cute whenever it does. You lean forward—it’ll strain your back to stay like this forever but for just a little hug with the gf after such a nice coupley activity you can deal, it’s whatever. “I think I finally get what the appeal is of like, staring at weird random gifs for hours on end even though they’re really short???? Like it’s repetitive to watch and all but it’s weirdly like… it’s COOL, and like, weirdly soothing???????? Hornier than gifs on the internet, though.”

“That, uhh, I think that depends on where you’re getting your gifs,” Alphys says dryly, and you can’t see her face but the smarm is just _dripping_ from her voice, and you can’t help but grin.

_“Clearly_ this means you gotta show me horny ones then!!!!” you say, and nuzzle against her shoulder. “Hey, lemme know when you’re clear for sex having. And, uh—if you’re up to it and all? I’ll watch next time too, if you’ll have me.”

Alphys releases your hands and reaches to hug you over the egg stack, the tiny mountain of her own orgasms. “Trust me, Undyne, I’ll have you whenever.”

“As long as you’re not sore from popping out thirty-some eggs.”

“As long as I’m not sore from p-popping out thirty-some eggs, yeah.” A pause. “You _counted?”_

The edges of your fins burn. _“Maybe a little?????????_ Look, maybe don’t invite me to your horny if you don’t want me to get horny about it?!!”

Alphys just giggles into your shoulder, that perfect post-exercise giddiness, so you wrap your arms around her too and don’t comment.


	3. over easy

Frisk, of all people, is the one to solve your conundrum in the end.

You have them and Chara over at your and Alphys’ pad while Asriel’s off with his dad for some political thing you don’t really care about. It’s always good to get quality time with Frisk in person, ‘cause thanks to their job their time to hang out with all their pals is sadly limited, and for Chara you suspect that this couples laid-back date night _(does_ it count as couples when one of the couples is two members of a polyam trio?) is filling their weekly leave-the-house quota.

As Frisk is the only person here with Actual Cooking Skills this also gets to be your and Alphy’s weekly chance to eat home cooking without the risk of exploding the kitchen. Frisk pulled all kinds of real cooking implements out of their phone and made some kinda buckwheat noodle soup with deep-fried tofu for lunch, and you’re waiting on their handmade taiyaki buns to finish baking.

You’ve ordered pad thai for dinner from the usual place, and since Alphys and Chara hate answering the door and you never know if the delivery person will be able to speak sign, that means you’re on pickup duty. So you’ve sorta halfway tuned out of the conversation, waiting for the sound of the doorbell; you’ve heard Alphy ranting about how much more difficult artificial insemination is for monsters than for humans or animals about a billion times before, anyway.

 _You know those kinds of dildo with a hole down the middle and removable tubing?_ you see Frisk signing from the corner of your eye, though, and THAT does get your attention.

“Ssssorta?” Alphys says, squinting one eye a little, while Chara shrugs.

 _They have dildos like that for alternative insemination that you can also just use lube or water with for fun if you like how it feels. A lot of them apparently aren’t designed that well because you’ve got to be able to take everything apart and wash it or it’ll get bacterial buildup, and everything I’ve seen online is human-shaped so it might not work for you, but I bet you could design something along the same lines that could get the job done,_ Frisk suggests, smiling winningly.

Alphys opens her mouth as if to reply, then closes it. “Some sort of release valve…? A manual one??”

 _The squirting dildos I’ve seen online all use hand pumps, yeah, but I was thinking like a remote,_ Frisk goes on innocently. _To keep your options open._

“Hmm,” Alphys says, crossing her arms to prop up her chin on her fist. “Hmmmmmm.”

“I’m sure you can figure it out,” Chara says dryly from their corner of the table. “You managed to make Frisk their goofy tentacle machine and the results were actually surprisingly nice and endearing instead of horrifying. A silicone dick with a real-life spunk repository will probably be baby stuff in comparison.”

You mouth _tentacle machine????????_ at them and Frisk while Alphys keeps _hmmmm_ ing and grabs idly for a napkin and a pen, so you won’t distract her. Frisk smiles and bites their lower lip and makes an ok sign at you, their eyes falling blissfully closed; Chara turns in their seat to gesture to Frisk with both hands like some kinda docent introducing a work of art in a museum, looking at you with mild irony and smiling eyes.

Needless to say you are VERY curious about this story, but the doorbell rings, cheating you of the chance to ask. You’re sure you’ll get it out of somebody at this table eventually.

 

 

Designing a practical dildo built for insemination becomes your wife’s passion project for the month, in between her scheduled lectures at local colleges and research facilities and her work blueprinting or coding or whatever-form-of-making the cool science gizmo du jour. You only get to oversee her sketching and 3D-printed prototypes sometimes, because in between _your_ work you’ve also gotta practice for the big-city charity recital you’re gonna be playing piano in, but it’s nice to see her having fun.

Chara dubs the drive to make the perfect dildo “Undyne’s Miltshake Brings Alphys To The Yard” and then has to go lie down melodramatically on the couch when none of you get the joke. After they _do_ explain, Alphys kids that they ought to write a curriculum for ancient memeology, which cheers them up a little bit.

You make smart-ass remarks from the sidelines, snap pics of the dongs to amuse friends for whom this won’t be TMI, and serenade Alph with your grand piano when she’s moved her work station to somewhere within sight of the living room. It is extremely great and the two of you are adorable in your very professional opinion.

She manages to time it so that she’s got the final version complete _exactly_ thirty days from couples dinner. You are in fact lounging on the couch after a day well spent helping the new assistant coach at Toriel’s school and overseeing one of the Ebott City nonprofit music classes for human kids, feet up and everything; you hear the thumping of excited footsteps and have enough time to cross your legs and muss your hair enticingly before Alphy bursts into view with her glasses crooked and a toy wang clasped triumphantly in her upraised fist.

“It is………” Alphys says, pausing dramatically to pose and adjust her glasses, “…… _complete!!!!”_

She’s so fucking cute you wanna put your goddamn fist through a wall. You grin at her and give her a thumbs up instead: “Nice.”

Said wang is cerulean blue and just barely translucent, so that when Alphy holds it up the way she is now, the backlighting from the lamps on the other side of the room makes it glow a little. Like all the rest of the toys she’s made for herself it makes a lazy Y shape, forking a little lower than halfway up the shaft; unlike the other toys she makes for herself, it has a very fat base that’s probably hollow, based on the way it looks more properly see-through than the rest.

 _“And,”_ Alphys goes on dramatically, grin broadening, “I-I also made sure t-to get a harness, so uhhh, we c-can t-take this b-baby on a t-test run w, whenever you like. W-we, ahh, I still have p-plenty of your milt s-stored up for trying so…”

“Here I thought you’d never ask,” you say, grinning back just as wide.

 

 

Watching your wife actually prep the dildo is strange and a little gross—and you’re usually pretty down for gross, but this ain’t your favorite flavor of it. She gets a little sterilized tupperware container of your come out of her tiny science fridge in the basement, deftly pops the bottom of the dildo loose with nimble claws, and removes a clear pouch made from stiff material and plastic tubes from it. She unfixes the tubes from the pouch, pours the come into it, and then reattaches the tubes and feeds the whole thing back through the bottom of the dildo and covers it with the silicone plug.

 _“Weird,”_ you say, leaning over her shoulder as she holds it back up to the light. “Do I have to, like… do anything with it to make sure it does the thing?”

Alphy produces a small remote in the same shade of blue with a button on it. “N-nope, unless you want to, uhhh, hold on to this. A-at least until, ahh, we’re used to it I think I’ll handle the t-timing.”

“Guess you _are_ the one who did all the research,” you say, and turn your attention to the harness. It’s a series of thick black belts of bumpy coarse threads attached to a pair of boxers in your size that look as close-fit as biking shorts, with a shiny open ring at the crotch where you guess the dildo’s supposed to fit through.

“Y-you should, ahh,” Alphy says, and you twist around so that you can properly see her. “Maybe let me p-put the dildo in there f-first before you put that on? I think it’ll b-be, be harder t-to neg-gotiate if you’re uh, already wearing it.”

“Makes sense,” you reply, and pick the harness boxers up to offer them to her. “Would you do the honors, babe?”

She chuckles: The sound’s half nervousness and half excitement, far as you can gauge. “S-sure thing.”

And she takes it off your hands, hunching over to fiddle with the straps and the blue dong with her brows drawn down fiercely, buck teeth working on her lower lip. She is just _so fucking cute_ you could honestly keel over, or scream, or like, pick up a refrigerator and throw it through a concrete wall.

Your wife pops back up and holds the harness shorts back up at you triumphantly, the dildo kinda bouncing in air from the motion and its own weight. “H-here!!”

You pull your boxers—the last article of clothing you had yet to remove—off and kick ‘em away before you accept the harness shorts from Alphy, and frowning a little with consternation you step one foot into a leg and then the other, and pull the things up.

These’re _snug._ Alphys knows your clothes sizes well, probably checked your exercise wear to make sure she’d be getting these at the right size, and as soon as you get ‘em past your knees they cling all the way up. Once they’re all the way on you become aware of the belts first—they cling around your middle at the waistline of the shorts, over your hips and your butt, heavy with a noticeable pressure that you like—‘specially the strap that loops down between your legs, tight against your crotch.

As for the dildo that the straps hold in place… honestly you think it just looks goofy there, since bits like this don’t really belong on many kinds of aquatic monster. It’s not like you _dislike_ it, just that it isn’t really your thing. But Alphy is ogling openly, so you guess if she’s enjoying the view that’s a definite plus. The flat base of the thing gives a nice firm pressure against your lower belly too.

“We need to use lube for this thing?” you ask.

“Uhhhh,” Alphys says, beginning to blush, “p-probably not this t-time.”

She shuffles out of her sweatpants and underwear and climbs up onto the bed still in her t-shirt. It’d probably upset her to ask her to take that off too—if she wanted to she already would’ve—so you swing yourself up after her as she lies on her back and squirms to get comfortable. The dildo wiggles just a little, pulling against the harness straps so your breath hitches.

“D-do you, uhh,” she says, and seems to get stuck for a moment. “Do you n-need help with this, o-or…”

“I think I got it,” you reassure, flashing a wide grin as you scootch up so that you’re crouched over her. “I’ve got a pretty good idea what to do from the hentais.”

 _“Undyne,”_ Alphys says, and starts to giggle.

You grab the dildo around the middle of the thing and regard Alphy’s cloaca, narrowing your eye a little. She made this thing and she knows best what her own junk can take, but the two heads on it seem a little far apart and you’re not quite sure how best to fit it in there.

Maybe watching your gears spinning, she reaches down with both hands to hold her cloaca open for you. “Just, uhh,” she says between breaths, “just p-push the, the tips in close and it’ll b-be fine.”

“Gotcha,” you say, and shift your hand up to squish the two heads of the dildo together as you guide it to her entrance and then in.

Alphy shudders underneath you, lets go of herself and reaches up with her left hand to grab your upper arm. You move your hands to plant ‘em on the mattress to either side of her, lowering your body so your hips’ descent’ll push the toy deeper in. It presses the tops of your thighs into the soft underside of hers, leaves you crouched straddling her tail; Alphys’ legs brush against your sides, against the sensitive gill tissue in your flanks, and you shudder too. The harness straps pull heavy against your crotch. It sends tingles all through your hips and makes you huff.

“Doin’ ok?” you ask. It comes out as mostly grunt.

“Oooohhh yeah,” Alphys says right by your ear on your bad side, then leans the side of her face against your cheek and nuzzles. “I’ve k-kinda wanted t-to try something like this for a, for a while, a-and it’s living up t-to all my fantasies??? I-I love it when you hold me a-and I love it when you p-p-p, plow me with my favorite t-t-toys and now I g-get the best of b-both worlds and it’s _romantic.”_

“Aww.” You turn your head ‘til you can sorta see what you’re doing and peck her on the cheek. “Glad that after all that unsexy fumbling I get to knock you up in _style_.”

Alphys moans and squeezes your shoulder, claws digging in a little. “Oh my g-god, I think I’m g-gonna dissolve on the spot if I don’t come soon, p-please just pound me??”

“You got it, doc,” you say, and put strength into your legs to push yourself up just a little bit before lowering back down. Alphy tightens her grip even further and squeaks.

Over the course of your relationship with Alphys you have watched, like, sixty bajillion explicit animes about catgirls getting fucked by various persons and creatures and in various configurations. You’ve also played, like, a few bajillion more games about or which feature sex, many of which also involve catgirls and dicks, since Alphys is nothing if not consistent in her interests. So, like, you _do_ know how this kind of sex works. It’s just that knowing this fact intellectually doesn’t automatically grant you perfect strap-on-wielding skills.

So you have to start slow just to make sure you’re moving right, and be careful so you don’t get too overenthusiastic and either pull out of Alphys entirely or ram her too hard. But hey, you figure that as long as she’s making squeaky noises and clumsily hugging at you with one arm and both legs, you’re probably doing a passable job.

Just plain old in-and-out does not really push the straps of the harness against your crotch firmly enough to do much for you, though. The weight of the dildo’s base against your skin, the tug of the straps on your legs and butt, and Alphys soft and squirming and clinging underneath you are all super mega ultra fucking hot, so much so that you gotta grab the sheets in both hands to keep from yelling right next to Alphy’s face, but it’s not enough direct pressure to get off to. You’re left wriggling your hips in awkward ways in between thrusts, squirming side to side and up and down before hitting on a curved back-and-forth hook motion like the slope of a hill that makes Alphys gasp and grinds you against that hot-spot strap in a searing stripe that slicks you up and soaks the crotch of the shorts in no time.

Alphy jolts under you and grabs you with her heels around the small of your back, pulling you in so you can’t thrust far anymore, whines _harder harder don’t stop yet_ and pulls herself up on the toy connecting you. You shift your weight into your legs again and grit your teeth and hump the strap between your legs rough and quick, jostling the dildo inside her as you strain to make the waves of pleasure radiating up through you continual, so the sensation’ll pile up instead of ever ebbing.

You can’t really tell if you come before or after her or while she’s coming; you just know your eye rolls back and your hips start jerking out of your control and you grunt _shit Alphy holy fuck_ and somewhere in there’s the click of a remote being pressed. Alphys’ long wordless moans turn into delighted gasps of “ohhhh, ohhh that’s _cold,_ oh Undyne _deeper,_ fill me up” and you let go, soak your shorts and the harness and probably the sheets beneath you too with warm sticky milt.

She keeps holding you for a while, both of you breathing hard; doesn’t let go ‘til it’s honestly starting to get kinda uncomfortable just sitting around in your own come with your hair starting to stick to your back. You nibble her shoulder and try to be patient, and then she releases you eventually, mumbling “think that’s all of it.”

Gingerly you sit up and scoot back. The dildo comes out of her cloaca with a wet _pop,_ both heads trailing fluid like strings of cheese on pizza; this is kind of a fixture of Alphy’s erotica of choice, so you’d always kinda imagined that was exaggerated and not something that happened in real life. The threads of fluid break then, and you blink down at the dildo as it dribbles down itself instead.

“Think we need’a change the sheets,” you say, making a face. You clenched your teeth so much your head’s starting to hurt a little.

“Can we do it later?” Alphys replies faintly. “I d-don’t wanna spill.”

 _That_ is hotter than you would’ve thought, and sorta takes you off-guard. “Sounds fair. Uh, I hope I didn’t manage to ruin this thing by nutting all over it?? And if I did, sorry???”

Your wife grins hazily up at the ceiling. “D-don’t worry,” she says, and you just kinda bask in the harmonious sound of a rare self-satisfied Alphys. “It’ll wash out.”


	4. scrambled

**Notes for the Chapter:**

> the first scene of this chapter contains a very brief reference to child grooming in regards to frisk's pregame backstory.

_I don’t know how much advice I actually have to give when it comes to flirting,_ Frisk says, pausing to push their glasses up on their nose and then shrug. _Especially when you’re trying to be sexy about it? You just… say a cute joke that’s a double entendre, or a compliment, or both. And then you strike a cute pose. Usually I wink but I don’t know how well that would work for you._

“Yeah, usually it just makes me look like either a colossal douchebag or a complete idiot,” you tell them. Then you frown and lean back in your seat. “And you used to hit on _literally everyone,_ Frisk, so I bet you have at least SOME tips, right?????”

They make a face. _I hit on everyone when I was a kid because before I wound up in the underground a lot of the grown-ups around me thought it was endearing and then they’d treat me nicer,_ they say. _Looking back on it I’m surprised I didn’t start to realize what was wrong with that when every time I flirted with a monster you all would either be weirded out or just pooh-pooh me and not take it seriously. My therapist had to talk to me about how that behavior was putting me in danger before I really thought about it, though._

You think back on Frisk pointing your spear at you back when you asked them what they wanted to drink, when Papyrus was making you hang out with each other. You remember being vocally weirded out that the human kid you’d been trying to kill for their soul was propositioning you, hoping that your gay ass was just mistaking what they meant and that they didn’t get the implication of their own actions. Now that Frisk is putting it like this, you get what they mean. “That’s grim,” is all you say out loud.

Frisk shrugs again, smiling apologetically. _As for now, I’d like to think I’m pretty good at sweet-talking Chara and Asriel in the bedroom, but that’s left me kind of… let’s say overspecialized? To give an example without any kind of kinky tmi, I dunno if Alphys would be that into being called a good boy._

Your eyebrows are basically approaching your hairline. “I’m not gonna lie that I’m curious, but I’m not that sure I wanna know, especially if Asriel—I’m _assuming_ this is about Asriel ‘cause you said _boy_ —hasn’t already cleared you to talk about it.”

_I could text him and ask,_ Frisk says helpfully, biting their lower lip a little as they grin.

“Maybe some other time???????” Saying this makes them laugh at you. Frisk’s laugh is very quiet, moving their shoulders more than anything else. “Besides, telling Alphy she’s a good girl’d probably just distract her with wanting to self-deprecate, and it’s hard to like… do a sexy when you’re having an argument about your wife’s moral character, y’know?”

Frisk makes a woeful face in sympathy. _Yeah, that kind of reinforcement’s kind of useless if your partner’s not even going to BELIEVE you. The stuff I do with Asriel to help him feel better would never work on Chara for a lot of reasons but that’s a pretty big one._

This conversation’s all kinds of educational even if you’re not learning the things you hoped you’d be able to. “Yeah, that’s the struggle here. A lot’s gonna depend on my ability to get Alphys all hornt up, but she like… you know her self-negativity issues. I wanna be able to do this _right,_ without putting my foot in it. She’s not that much help either, like, when I ask her what she’d want to hear she just deflects and changes the subject ‘cause she’s embarrassed.”

Most of your wife’s kinks are for fantastical situations, anime stuff; when they involve her body at all it’s acts, functions, things that she can do to you or that you can do to her, with as little attention paid to her looks as possible. _You_ think that her being soft and small and cute is sexy as hell, but if she’s feeling bad about herself it only makes things worse for you to say so. It’s a bad idea to try to rely on the weather for this one, ‘cause Alphy’s spirals always get more drastic when she knows things hinge on her mindset, and knocking her up _has_ to be deliberate.

_I wish I could do more to help,_ Frisk says. They seem genuinely regretful. _But when I’M not feeling good about my body I try to fight that by going out of my way to use it, and have my partners admire it, and trust that they’d say no to things that they don’t want to do so I know they’re being sincere in their words and actions. But if you’re worried that Alphys won’t believe you over what she thinks about herself, then…_

“Why do come-ons have to be so DIFFICULT,” you complain, slouching back in your seat.

“What’s so difficult about ‘em?” says a familiar voice. You and Frisk both turn towards the door to see Sans stepping through, grinning wide, hands shoved into his pockets.

You give him the most bone-dry glare you can drum up. “Then let’s hear you come up with a good one right now, buddy.”

“A’right.” He holds up his hands, spreading out his bony fingers. “Your eyes………… are an ocean. Your breast………… are _also_ an ocean.”

Frisk starts giggling so hard beside you they lean into your shoulder. The corners of your mouth want to twitch up something fierce; you force yourself to scowl instead of cackle. “That doesn’t even make sense!!!!!!!!!!!!!!! And me and Alph don’t have breasts anyway!!!!!!!!!!!!!!!!!!!”

_You SO got that one from Chara, don’t even TRY to lie to us,_ Frisk says.

“But it’s _funny,”_ Sans says, returning one hand to his pocket and wagging the pointer finger of the other. “You gotta give me that.”

“Either stop being deliberately unhelpful or fuck off,” you tell him.

“Okay, okay. But before I cha cha real smooth outta here? If you want real _good_ sexy talk advice and not even Frisk can help ya, I’d ask Tori.”

You frown. “Seriously???”

Sans nods. “I’ve legit seen her make a grown man nut just by talking at him, on more than one occasion. And before you just go _oh well she can only do that ‘cause it’s Gorey and he’s easy,_ sometimes the grown man in question is me.”

Before you can decide whether this is way more information about both Asgore and Sans that you ever wanted to know or press Sans for more details, he grins and winks and moonwalks right back out the door he came through, using his weird physics-breaking magic to teleport away to fuck knows where.

 

 

“You wanna give it a try tonight?” you ask Alphy over dinner, and she frowns at you and finishes slurping her instant noodles and then puts her fork down carefully.

“Yyyyyyyyyyyyyes?” she says hesitantly, narrowing her eyes. “Why all of a sudden?”

You grin real wide. “I’ve been doing _secret training_ all week to learn to talk sexy better,” you tell her. “You could probably make an anime montage out of it. I got advice from friends and everything. I now have a black belt in come-ons. I wanna show off my newfound prowess, and we’ve been talking about having babies for like _forever._ So if you’re cool with it? Tonight I wanna see if I can knock you up.”

Alphys had been listening to this with narrowed eyes and a pursed mouth, but as soon as you get to the last bit her eyes widen and she blushes.

“W-well,” she blusters, turning her gaze back down towards her food. “Well, if you’re so c- _confident_ about it, then why d-don’t you show me what you’ve g-got, you b-big smarty pants.”

 

 

Years ago when the topic of Kids Someday Maybe first came up, Alphy talked to you about a lot of things concerning practical matters.

Her kind are a special case amongst lizard monsters in that all of them are egg-producing. They don’t necessarily need a sperm-producing partner to have kids; they can also reproduce through a process called parthenogenesis, which she tried to give you the whole complicated Nerdy Crap Explanation for and which you tried to listen to but did not really absorb. The short, easy-to-understand version, though, is that she can make eggs with babies in them all by herself.

“It g-gets kind of complicated in that, uhh, I still need to have _sex_ t-to have kids,” she went on, staring at the corner of the ceiling like she does when she gets really embarrassed, “b-because I only ovulate on orgasm, b-but I’m _also_ the same as other m-monsters so my b-body just makes slugs, makes d-dud eggs I guess, unless I actively w- _want_ kids during sex.”

“Which is good I guess because we don’t necessarily want to have a billion babies every time we bang,” you filled in.

“Yes! B-but also when we d-decide we, ahhh, _do_ want to have kids it could get a little, uhhh, _interesting._ Since it’s g-going to depend… completely on my mindset.”

You and Alphys had been together long enough for you to see what the trouble was going to be _there._

But, well, at the time you’d just shrugged and said that you could worry about climbing that hill when you got to it. No need to spend all that time getting anxious!!!! Anxiety could fucking get in line and wait its turn until the topic came up naturally!!!!!!!!!! SO THAT WHEN THE TIME ACTUALLY DID COME, YOU WOULD ALREADY HAVE A PLAN IN PLACE TO PUNCH IT INTO THE STRATOSPHERE, ‘CAUSE NEITHER OF YOU INVITED IT TO BED!!!!!!!!!!!!!!

And you do have a plan! Sort of! So anxiety can _suck it._

You and Alphy both undress before getting up onto the bed—or, well, you do; Alphys takes her leggings and her dress off and stands there in her tank top and pushes her glasses up on her forehead to cover her face with both hands. You look over your shoulder at her while you chuck your clothes in the general direction of the laundry basket. Now she is whispering _“aaaaaaaaaaaaaaa”_ in a tiny voice.

You wait for a couple seconds to see if she’ll stop on her own. She just pauses for breath and goes back to whisper-screaming, so you turn to face her and lean down a little.

“Is that a good aaaaaaa or a bad aaaaaaa?” you ask.

Alphys disengages one hand from the face-covering to wave it around in the air. “It’s an I-can’t-believe-this-is-finally-happening aaaaaaa???”

“If you’ve changed your mind about tonight being good,” you begin, but she cuts you off by shaking her head so vigorously her whole body shakes with it, tail whipping in circles like she’s dancing.

_“No it’s great!!!_ I-I just don’t want to, to, to hyperventilate in the m-middle of trying to fuck b-because that would be _embarrassing as hell._ I’d rather scream really really quietly.”

“Hence the aaaaaaa,” you supply.

She nods and then gets back to it: _“aaaaaaaaaaaaaaaaa.”_ You cannot help but grin; past you was a total dumbass to have ever thought even for a second that Alphy’s cuteness is something you could get used to. You’re ready to have a ONE-WOMAN RIOT in this bedroom.

“Can I pick you up?” you ask.

She lashes her tail more quickly but nods, face still covered in both hands. You bend lightly at the waist and the knees to get your arms around her and scoop her up. Alphys thinks she’s _heavy_ but she super isn’t, you can balance her in one hand and barely even strain yourself; what she _is_ is soft and squishy like marshmallow fluff. _Better_ than marshmallow fluff, because when you hug her she _squirms_ and makes noise until you’re breathing in huffs and your crotch is wet and burning and your lower belly feels bloated and heavy with unspent roe.

“Can I kiss you,” you ask, and she nods up and down so emphatically her glasses bounce. You shift your hold on her so that you’re more properly facing each other, and she squeezes your sides between her thighs, and you make the fuck out with her face: Smooch her up and down the edge of her lips ‘til she opens up, slip your tongue into her mouth to play with hers ‘til you’ve properly coaxed it into your mouth and can suck on it. She makes a noise. You sit on the mattress so your awkward dry humping to the rhythm of your kisses won’t send you both pitching over onto the floor.

When you start getting short of breath you pull back to kiss your wife’s cheeks, her shoulders. You think back on your lessons, at Toriel raising her eyebrows and smiling the demure little smile that actually meant she was thinking wicked things, about her calm voice telling you _Most important is to communicate: When in doubt, check in with her before progressing._ At the time you flushed all the way to your gills, getting called on that; she was right, though. You can’t cast a spell to fix Alphy’s issues but sometimes it’s better to just ask instead of trying to tap-dance around things like a jackass hoping you’re never gonna set her off.

“’Zit okay if I tell you you’re cute?” you ask, panting.

“You sound like Frisk when you say it like that,” Alphys says, and then: “Y-yes.”

“Well, you’re cute,” you tell her, closing your eye and running your hands down her back in slow strokes, one after the other, until you’re both shuddering. _“God._ You’re so hot, it makes _me_ so hot just holding you like this, you’re all warm and soft and solid and _real._ I’m still not over it even though we’ve been together for like _years_ now, you know I used to jack off thinking of holding you just like this, _shit_ babe, you make me wanna come.” She shivers and squeezes your sides tighter between her thighs; you nibble her shoulder and go on. “I wanna make _you_ come. I wanna put a baby in you every time you come. I wanna watch you get all soft and round while the eggs are growing in you knowing I put ‘em there, I wanna see what it looks like when you lay _real_ ones.” Alphy is whimpering against you now, her hands in claws on your arms, rubbing her slippery cloaca against your belly. “How many do you want?”

“Undyne oh my g- _god,”_ she groans. “C-can we start with one _right now,_ i-if you d-don’t put your fingers in me I’m g-gonna _die.”_

You grin broad and tuck your left arm tightly around her waist, and shift your right back so you can tuck your hand between you, palm-up. Alphy’s already way wet, so you don’t even have to tease her; your fingertips just slide right in.

She grabs you harder, legs starting to shake. You slip your fingers in deeper, spreading them along the silky-smooth walls of her; Alphys groans again at a higher pitch, so you rub a little harder, dragging your fingertips back and forth, tugging your arm back and forth to thrust in and out without having to strain your wrist in weird directions. She squeaks and whines and clutches at you with a little feathery _oh oh oh_ ululating in the back of her throat as she comes.

You squirm where you sit a little because _god_ that took like no time at all, that is _so hot,_ this is nowhere near the minefield you were fearing it might turn out to be. You need to buy Toriel like… flowers or an escargot cookbook or some shit as thanks.

“Don’t pull out,” Alphys moans before you can try. Your whole crotch, your lower belly _aches._ “I w-want m-m-more.”

“As many as you want, babe,” you say, kissing the side of her neck. “Can I lay you back?”

“Yeah,” she says. You rise up on your knees and lean forward, lifting Alphy up so she can reposition her tail before you rest her out along the mattress. Then you pull your arm out from underneath her so you can balance your weight on it too, not just your shins.

You take a minute to just look at her underneath you, panting, glasses crooked, eyes unfocused, shivering a little with your fingers still inside her. You can’t help it—you bob your head to plant a smooch at the end of her snout. “You’re so goddamn _cute_ when you nut.”

Alphy whines and kneads at your shoulders. “Three,” she says.

“Huh?”

“I w-want three,” she repeats, and then falls silent, blushing up at you under her scales.

You swallow. You want to come so bad it nearly hurts. “Three’s a good number,” you agree, and you start to stroke her again.

She whines and spreads her legs further, giving you a clearer view of her belly and her cloaca, of the pale scales on the underside of her tail. You curl your fingers as you play with her, rubbing around her hemiclits until she whines; then you straighten your fingers out and thrust for a while. If she weren’t breathing so hard you’d want to just lean in and catch her mouth with yours; you compromise with yourself by leaning down to kiss her face, her chest and shoulders.

“Undyne,” she says soft, breath tickling your fin, and then she clenches up underneath you as she comes, nails biting into your shoulders. She squeezes your fingers tight, then tighter, then loosens and goes slack. You pull your hand away, plant it on the sheets so you can give your left arm a rest supporting you.

Alphys breathes out and releases you to straighten her glasses. “I-I need a break down there,” she puffs, and then gives you her best and most wicked smile. “A-and I bet you want a little attention by now t-too, right?”

You bite your lip a little as you grin down at her. “Yeah, _god,_ if you don’t mind…?”

She nods, not making a move to sit up. “W-well, why don’t you come up here and fuck my face then?”

You suck your breath in. _“Fuck,_ don’t mind if I do.” It’s awkward having to half shuffle half waddle forward on  your knees, your back cracks a little, but you do it, eager for your promised reward.

“Just, uhh, warn me when you’re gonna come so I don’t choke,” she says, and you grip the headboard and nod. Alphy grabs your ass to reel you in, and you crouch over her shoulders.

At the first roll of sticky-wet tongue across your crotch, you demurely throw your head back and yell, holding the bedframe tighter so you won’t thrust forward with so much strength you risk hurting her neck or knocking her teeth out. She slurps at you happily, long flexible tongue wiggling and coiling, and you let your eye roll back and arch your spine and hump her mouth.

“Al, _fuck,_ your tongue,” you moan. “Oh fuck, babe, here it comes—”

She _moans_ right up into your crotch and you _push_ and cascade roe down her throat, jerking and shaking as she gulps and laps at you. Each lick and each touch seems to flutter through your muscles all the way up your gills and to your fins, making your hair stand on end; you whine and grunt and grind awkwardly into her face ‘til you haven’t got anything left to give, and slow to a stop.

It takes _effort_ to get back up on your knees and give Alphys space. When you look down blearily she’s licking her chops with an adorably smug expression.

“That was fast,” she tells your crotch.

You move very awkwardly back down the bed so you can sit properly. “Well, I was really horny,” you say, turning to look at her—her head’s on your bad side. “’Cause you’re really hot.”

“There you go again with the flattery,” she says.

You stretch. “It’s not flattery, Al, I legit can’t spooge like that just ‘cause I’m tryin’ to be _nice_ or some shit.”

“If you say so.” A pause; then she tucks her chin to her chest and eyes you. There’s spatter on her glasses, but no roe stuck there; if there was she probably stretched her tongue out to lick ‘em off. “A-are you too tired to work on number three…?”

“I don’t think I’m gonna get off again tonight, but I’m not too tired to get _you_ off.” You stretch again, rotating your waist to work out any kinks in your muscles, and then roll back onto your knees. You reach out a hand to stroke her belly and she goes very still, looking at you. “Would it be… I dunno, uncomfortable to keep sweet-talking you?”

She narrows her eyes and puffs out her cheeks. “You can do it if you don’t go _too_ overboard,” she hedges. “I d-don’t really get what the appeal is b-but Frisk was telling me that I should t-try to listen when you want to say, ahh, nice things ab-bout me anyway.”

You make a face to hide your smile. “That meddler,” you say.

“And h-hey, just who were you g-getting your lessons from?” she asks, half-grinning.

_“That,”_ you say, running your hands slowly up and down Alphy’s thighs until she shivers, “is a whole story that I wanna tell you some other time, when I know you can pay attention to it. You’ll laugh, probably. It’ll be great.”

“Well, if you s-say so,” Alphys says. And: “Oh,” as you play your thumbs in swirls at where her thighs converge with the base of her tail.

_Be honest, and be confident, and be kind,_ Toriel had told you, so instead of trying to come up with something canned and suave you lean down to kiss Alphy’s belly. Her right foot pops up a little like she’s ticklish but she doesn’t try to dislodge you.

“Soft,” you comment, and kiss again. “Warm.” You punctuate this with another smooch. “God, is it gonna be safe to still fuck you like normal after this? I don’t wanna mess anything up, or risk adding any extras to the three we agreed on.”

“It’s g-going to be about a month or two b-before I lay them,” she says, breath catching. Glancing up at her shows you that her pupils are wide. “B-but I’ll, ahh, I’ll l-look stuff up t-to make sure. If I _have_ t-to be celibate I’ll live, though, it’s n-not that long.”

“Guess I better make this one real nice just in case.” You trail kisses in meandering zigzags down her stomach as you palm her cloaca, buy yourself time ‘til she’s squirming up into the hell of your hand. Then you trail your fingertips down, slip three into her. She moans.

“We couldn’t take care of a billion kids,” you say, a little less casually than you were aiming because who _can_ be casual at the sight of Alphys wiggling around whimpering like this?—“but god I wish I could keep going all night, fill you right up, make you even _softer.”_

Your wife curls her legs up on the mattress, gripping the sheets with her toe claws, her knees squeezing on your shoulders. _“Undyne.”_

You dip your chin to kiss her right at the edge of her cloaca and begin to move your hand in slow steady strokes like waves. In, slow down; out, speed up, then slow. Back in. Alphys _writhes._ “I love the way you sound when I take you slow.”

“It feels so _g-good.”_ The sheets make a whispery sound as she bucks her head back; the mattress springs squeak. “Undyne—c-come on, make me come, I want… I w-want to have your baby, Undyne…”

You’re not up to another orgasm but you still squirm to rub yourself against the sheets a little, hearing that. You curl your fingers in her, gently suck her belly flesh into your mouth and nibble, rolling it under your tongue so there’ll be a mark tomorrow; her breath burbles in the back of her throat and she constricts on you, rolling her hips on your hand.

You let go of her when she relaxes, wipe your fingers off on the sheets and crawl up so you can fling your arms around her. Alphys breathes out long and slow and presses her forehead against your bare chest, glasses digging into your collarbone.

“You’re an evil woman,” she mumbles.

“I am???” you ask, frowning down at her.

“This was _so hot_ and I know I’m g-gonna want to r-rub one out to it forever b-but I don’t think I can do that without risking knocking myself up even more.”

You try to muffle your cackles but really only manage to subdue them to a snort.


	5. eggs in a basket

You pull your hair back from your face in both hands and fondly regard your beautiful wife: Her chest and stomach and thighs still heaving with her breath, her flushed face, her beatific smile…

You also regard the mess you’ve made of the bed: Roe everywhere. _Eggs_ everywhere, slugs, freshly laid and still steaming a little. You are glad that you and Alphy went all out this time and actually covered the bed in a vinyl tarp before you got down to mattress boogieing.

After several long moments of regarding, once Alphys is breathing normally again, you gesture feebly at the wreckage. “So, uh… what are we gonna _do_ with all these now that we’ve got ‘em?”

Alphy lifts up on her elbows and narrows her eyes, giving you a Look.

You narrow your eye back, and wonder if the same thought has occurred to her that’s occurred to you.

 

 

You sit across the table from each other, both pausing in lowering your utensils. You have a spoon and fork; Alphys, who you suspect Chara would be affectionately calling a ‘true weeaboo’ right about now, has one of those flat ladle-looking spoon things and a pair of chopsticks.

She broke out the _nice_ sticky rice for this, chucked it in the rice cooker so that neither one of you could totally destroy it the way you both always risk when it comes to food. The bowls are filled almost to brimming with the stuff. The main difference to the dish is that where the roe in the photos Alphy googled for you were salmon or something, bright little orangey-red balls, the rice in these is coated in a layer of roe that’s pearlescent white.

The egg yolks are different too, deep orange where the yolks in the pics had mostly been yellow. “T-that’s good, though,” Alphys said after cracking them on top of her own bowl. “Darker yolks m-mean that the uhh, that what laid them is healthy.”

You agreed that this is probably good.

Alphy takes a deep breath and pokes one yolk with her chopsticks so it breaks, spreading the runny gold all through the layer of roe and the rice underneath. She grabs a clump of the mixed-up stuff in her chopsticks and takes a big bite.

“Mmmmmmm,” she says, eyes shuttering blissfully. She goes on with her mouth half-full, already grabbing for a new bite: “Oh mah gah, ihh ho _‘ooey?????”_

She swallows and sees the look on your face and pauses in shoveling a second into her mouth. “D-don’t worry. L-like I said, the heat from the rice will cook the eggs a-and we made sure to clean everything c-carefully beforehand, so…”

You nod and scoop yourself a spoonful. She’s right—it’s actually super fucking tasty???? The melty consistency of the egg, the warm rice, and the squishy mini-tapioca bubble texture of the roe go together like a dream?????? You managed to make _real breakfast??????????_

With your _bodies??????????????????????????????_

“This is,” you say in between bites, “hands-down the most fucked-up kinky thing we’ve ever done together.”

Alphys nods and turns red and starts to giggle.

**Notes for the Chapter:**

> so, there is a japanese dish that is called ikura tamago-kake don, which is a bowl of rice topped in fish eggs and also bird eggs. a google image search for いくら卵かけ丼 ought to turn it up, but here are [some examples](https://twitter.com/theouls/status/970488617389797376) [on twitter](https://twitter.com/zenkoku_gurume/status/955378634914652160).
> 
> i considered naming this shitpost after the dish in question, but i feel like that would've ruined the joke.


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